<template>
  <div :class="{active:isActive}" class="share-dropdown-menu">
    <div class="share-dropdown-menu-wrapper">
      <span @click.self="clickTitle" class="share-dropdown-menu-title">{{ title }}</span>
      <div :key="index" class="share-dropdown-menu-item" v-for="(item,index) of items">
        <a :href="item.href" target="_blank" v-if="item.href">{{ item.title }}</a>
        <span v-else>{{ item.title }}</span>
      </div>
    </div>
  </div>
</template>

<script>
  export default {
    props: {
      items: {
        type: Array,
        default: function () {
          return []
        }
      },
      title: {
        type: String,
        default: 'vue'
      }
    },
    data() {
      return {
        isActive: false
      }
    },
    methods: {
      clickTitle() {
        this.isActive = !this.isActive
      }
    }
  }
</script>

<style lang="scss" rel="stylesheet/scss">
  $n: 8; //和items.length 相同
  $t: .1s;
  .share-dropdown-menu {
    width: 250px;
    position: relative;
    z-index: 1;

    &-title {
      width: 100%;
      display: block;
      cursor: pointer;
      background: black;
      color: white;
      height: 60px;
      line-height: 60px;
      font-size: 20px;
      text-align: center;
      z-index: 2;
      transform: translate3d(0, 0, 0);
    }

    &-wrapper {
      position: relative;
    }

    &-item {
      text-align: center;
      position: absolute;
      width: 100%;
      background: #e0e0e0;
      line-height: 60px;
      height: 60px;
      cursor: pointer;
      font-size: 20px;
      opacity: 1;
      transition: transform 0.28s ease;

      &:hover {
        background: black;
        color: white;
      }

      @for $i from 1 through $n {
        &:nth-of-type(#{$i}) {
          z-index: -1;
          transition-delay: $i*$t;
          transform: translate3d(0, -60px, 0);
        }
      }
    }

    &.active {
      .share-dropdown-menu-wrapper {
        z-index: 1;
      }

      .share-dropdown-menu-item {
        @for $i from 1 through $n {
          &:nth-of-type(#{$i}) {
            transition-delay: ($n - $i)*$t;
            transform: translate3d(0, ($i - 1)*60px, 0);
          }
        }
      }
    }
  }
</style>
